Do Muslims believe that Jesus was God?

No, Quran tells us that Jesus(PBUH) is a mighty messenger of Allah sent to the people of Israil. (5) (Remember) when the angels said: "O Maryam (Mary)! Verily, Allah gives you the glad tidings of a Word ("Be!" - and he was! i.e. Iesa (jesus) the son of Maryam (Mary)) from Him, his name will be the Messiah Iesa (jesus), the son of Maryam (Mary), held in honour in this world and in the Hereafter, and will be one of those who are near to Allah."

( سورة آل عمران , Aal-e-Imran, Chapter #3, Verse #45)

6) And He (Allah) will teach him (Iesa (jesus)) the Book and Al-Hikmah (i.e. the Sunnah, the faultless speech of the Prophets, wisdom, etc.), (and) the Taurat (Torah) and the Injeel (Gospel).

( سورة آل عمران , Aal-e-Imran, Chapter #3, Verse #48)

8) Then when Iesa (jesus) came to know of their disbelief, he said: "Who will be my helpers in Allahs Cause?" Al-Hawarioon (the disciples) said: "We are the helpers of Allah; we believe in Allah, and bear witness that we are Muslims (i.e. we submit to Allah)."

( سورة آل عمران , Aal-e-Imran, Chapter #3, Verse #52)

(10) And they (disbelievers) plotted (to kill Iesa (jesus) ), and Allah planned too. And Allah is the Best of the planners.

And (remember) when Allah said: "O Iesa (jesus)! I will take you and raise you to Myself and clear you (of the forged statement that Iesa (jesus) is Allahs son) of those who disbelieve, and I will make those who follow you (Monotheists, who worship none but Allah) superior to those who disbelieve (in the Oneness of Allah, or disbelieve in some of His Messengers, e.g. Muhammad SAW, Iesa (jesus), Moosa (Moses), etc., or in His Holy Books, e.g. the Taurat (Torah), the Injeel (Gospel), the Quran) till the Day of Resurrection. Then you will return to Me and I will judge between you in the matters in which you used to dispute."

( سورة آل عمران , Verily, the likeness of Iesa (jesus) before Allah is the likeness of Adam. He created him from dust, then (He) said to him: "Be!" - and he was.

( سورة آل عمران , Aal-e-Imran, Chapter #3, Verse #59)

Aal-e-Imran, Chapter #3, Verse #55) Verily! This is the true narrative (about the story of Iesa (jesus)), and, La ilaha ill-Allah (none has the right to be worshipped but Allah, the One and the Only True God, Who has neither a wife nor a son). And indeed, Allah is the All-Mighty, the All-Wise.

( سورة آل عمران , Aal-e-Imran, Chapter #3, Verse #62)

And because of their saying (in boast), "We killed Messiah Iesa (jesus), son of Maryam (Mary), the Messenger of Allah," - but they killed him not, nor crucified him, but the resemblance of Iesa (jesus) was put over another man (and they killed that man), and those who differ therein are full of doubts. They have no (certain) knowledge, they follow nothing but conjecture. For surely; they killed him not (i.e. Iesa (jesus), son of Maryam (Mary) ):

( سورة النساء , An-Nisa, Chapter #4, Verse #157)

But Allah raised him (Iesa (jesus)) up (with his body and soul) unto Himself (and he is in the heavens). And Allah is Ever AllPowerful, AllWise.

( سورة النساء , An-Nisa, Chapter #4, Verse #158)

O people of the Scripture (Jews and Christians)! Do not exceed the limits in your religion, nor say of Allah aught but the truth. The Messiah Iesa (jesus), son of Maryam (Mary), was (no more than) a Messenger of Allah and His Word, ("Be!" - and he was) which He bestowed on Maryam (Mary) and a spirit (Rooh) created by Him; so believe in Allah and His Messengers. Say not: "Three (trinity)!" Cease! (it is) better for you. For Allah is (the only) One Ilah (God), Glory be to Him (Far Exalted is He) above having a son. To Him belongs all that is in the heavens and all that is in the earth. And Allah is AllSufficient as a Disposer of affairs.

( سورة النساء , An-Nisa, Chapter #4, Verse #171)

And in their footsteps, We sent Iesa (jesus), son of Maryam (Mary), confirming the Taurat (Torah) that had come before him, and We gave him the Injeel (Gospel), in which was guidance and light and confirmation of the Taurat (Torah) that had come before it, a guidance and an admonition for Al-Muttaqoon (the pious - see V.2:2).

( سورة المائدة Surely, they have disbelieved who say: "Allah is the Messiah (Iesa (jesus)), son of Maryam (Mary)." But the Messiah (Iesa (jesus)) said: "O Children of Israel! Worship Allah, my Lord and your Lord." Verily, whosoever sets up partners in worship with Allah, then Allah has forbidden Paradise for him, and the Fire will be his abode. And for the Zalimoon (polytheists and wrongdoers) there are no helpers.

( سورة المائدة , Al-Maeda, Chapter #5, Verse #72)

, Al-Maeda, Chapter #5, Verse #46) The Messiah (Iesa (jesus)), son of Maryam (Mary), was no more than a Messenger; many were the Messengers that passed away before him. His mother (Maryam (Mary)) was a Siddiqah (i.e. she believed in the Words of Allah and His Books (see Verse 66:12)). They both used to eat food (as any other human being, while Allah does not eat). Look how We make the Ayat (proofs, evidences, verses, lessons, signs, revelations, etc.) clear to them, yet look how they are deluded away (from the truth).

( سورة المائدة , Al-Maeda, Chapter #5, Verse #75)